Horizontal lapping wheels



June 21, 1955 EfR. MAGNUs 2,711,057

HORIZONTAL LAPPING WHEELS l INVENTon EDWARD R. MAGNus June 2l, 1955 E, R. MAGNus HORIZONTAL LAPPING WHEELS 2 Sheets-Sheet 2 Filed Julyl 11, 1952 INVENToR. EDWARD R. MAGNus HORIZONTAL LAPPIN G WHEELS Edward R. Magnus, St. Louis, Mo., assignor to Snowhill Manufacturing Company, St. Louis, Mo., a corporation of Missouri Application July 11, 1952, Serial No. 298,287

6 Claims. (Cl. 51-109) This invention relates in general to certain new and useful improvements in grinding machines and, more particularly, to a horizontal lapping wheel.

lt is the primary object of the present invention to provide a grinding wheel which is an entirely self-contained unit and is adapted for accurately lapping, honing, grinding, sharpening, and finishing all types of flat surfaces.

lt is another object of the present invention to provide a device of the type stated which is compact and can be readily transported from place to place or from position to position upon a Work bench.

lt is also an object of the present invention to provide a device of the type stated which makes it possible for the machinist to achieve a high degree of precision in grinding, honing, or lapping operations and achieve a type of finely ground surface substantially of the same type as heretofore obtained by hand lapping methods.

It is also an object of the present invention to provide a device of the type stated which is simple in construction and economical in cost.

It is also an object of the present invention to provide a device of the type stated which is rugged, durable, and capable of highly satisfactory speed control.

With the above and other objects in view, my invention resides in the novel features of form, construction, L

arrangement, and combination of parts presently described and pointed out in the claims.

In the accompanying drawings (two sheets)- Figure l is a top plan View, partly broken away and in section, of a horizontal lapping Wheel constructed in accordance with and embodying the present invention;

Figure 2 is a vertical sectional view taken along line 2 2 of Figure l;

Figure 3 is a Vertical sectional view taken along line 3-3 of Figure 2; and

Figures 4, 5, and 6, are fragmentary sectional views taken along lines 4-4, 5-5, and 6 5, respectively, of Figure 3.

Referring now in more detail and by reference characters to the drawings, which illustrate a preferred embodiment of the present invention, A designates a lapping machine comprising a relatively heavy circular base formed preferably of cast iron or other suitable material and provided with an upstanding annular rim 2 extending around its outer periphery. Formed integrally upon the upper face of the base 1 is an upstanding block-shaped boss 3 projecting upwardly for a substantial distance above the plane of the upper face of the rim 2. Y Similarly formed upon and projecting upwardly from the upper face of the base 1 are two short bosses 4, 5, located on opposite sides of the boss 3 along the same diametral line and spaced equidistantly inwardly from the rim 2 on opposite sides of the base 1. Finally, the base 1 is provided with an integrally formed upwardly projecting centrally located circular boss 7, the upper face of which lies substantially in the same plane as the upper face of the rim 2. The boss 7 is diametrally reduced to provide nited States Patent O 2,711,057 Patented June 21, 1955 an upstanding central shaft 8, which is, in turn, provided in its upper face with a centrally located conical recess 9 for receiving a single polished steel ball 1t), which is of such diametral size as to project upwardly out of the recess 9.

Upon its under face, the base 1 is drilled and tapped at four equidistantly spaced points for receiving short bolts 11 extending through and tightly securing circular rubber foot-members 12 by which the lapping machine A may be supported upon any suitable flat surface, such as the top of a table or work bench. Secured by means of short bolts 13 to and extending around the outer peripheral face of the rim 2 is a cylindrical skirt member 14 which extends upwardly above the rim 2 for a height which is somewhat less than the height of the shaft 8. Around its upper peripheral margin, the skirt 14 is preferably provided with an annular inwardly beaded trimming-collar 15 and at diametrally opposite points around its surface, preferably midway or its height, the skirt 14 is provided with a pair of conventional handles 16. Set into the skirt 14 in alignment with the radial center line of the boss 3 is a grommet 17 for slidably supporting a locking-rod 18 which projects therethrough and at its inner end is slidably mounted in a radial bore 19 drilled through the boss 3. Disposed concentrically around a portion of the locking-rod 1S is a compression spring 2l) abutting at one end against the inner face of the grommet 17 and at its other end against an annular washer 21 rigidly secured to the locking-rod 18, thereby normally biasing the rod 18 inwardly. At its outer end, the lockingrod 18 is provided with a suitably knurled knob 22.

The upper face of the base 1 is provided with two aligned pairs of shallow conically bottomed recesses 23, 23', 24, 2d', arranged along lines parallel to and equidistantly on oposite sides of the longitudinal axis of the rod 18. Furthermore, the apertures 23, 24, are located equidistantly on opposite sides of the 4shaft 8 with respect to the corresponding recesses 23', 24', thereby, in eiect, forming the four corners of a rectangular configuration, so to speak, and being adapted for receiving downwardly projecting pointed ears 25 formed integrally upon the lower corners of rectangular plates 26 which extend, respectively, upwardly therefrom in substantially parallel relation on opposite sides of the shaft 8 and `are provided, adjacent their lower margins, with enlarged apertures 27 for loosely engaging the prong-shaped ends 28 of spring-leaf members 29, which are, in turn, secured by means of bolts 30 to the bosses 4, 5, for holding the plates 26 resiliently downwardly in the recesses 23, 23', 24, 24'. Set into the plates 26, adjacent their upper margins, are symmetrically located grommets 31, 31', for slidably receiving the opposite ends of stabilizing rods 32, each of which is centrally provided with a rigidly secured shoulderforming washer 33. Disposed concentrically around each rod 32, on opposite sides of the washer 33, are compression springs 34, 35, respectively abutting at their outer ends against the inner faces of the grommets 31, 31', for normally biasing the plates 26 outwardly away from each other.

Mounted centrally on and extending vertically along the outer face of each of the plates 26 are identical electrical motors 36, 36', having lead wires 37 connected through conventional toggle switches 33, 38', and a` connectorcord 39 to a source of electric power (not shown). The motors 36, 36', are provided with vertically upwardly projecting drive shafts 4d, dll', which are relatively short spaced concentric grooves 45. Also formed integrally upon and projecting downwardly from the under face of the wheel 43 is a tubular bearing sleeve 46 which eX- tends around the shaft 3 and is bearinged thereon by means of a bushing sleeve 47 formed of any suitable antifriction material. At its lower extremity, the sleeve 4o is integrally provided with an outwardly projecting annular flange 4? for releasable engagement with the inwardly projecting end of the locking-rod 18, whereby the wheel 43 is held against unauthorized removal. By withdrawing the locking-rod 1S, the wheel 43 may be bodily lifted out for change or replacement. During replacement, the motors 36, 36', must be pushed in to clear the start-like rim 42. This can be accomplished manually or in any other suitable manner.

The downwardly presented interior face 49 of the sleeve 46 is concentrically bored, as at Sil, to provide a feeding shoulder adapted to rest bearingwise against the steel ball 10. lt should be noted in this connection that the outer diametral size of the wheel 43 is preferably the same as the outer diametral size of the trimming rim l5, although, if desired, the wheel can be of somewhat larger size and, furthermore, the diametral size of the rim d2 is such that it will iit loosely and freely downwardly within the upper region of the skirt 14 and trimming rim 15.

As will be seen from Figure 2, the compression springs 34, 35, on the rod 32 operate to swing the plates 26 outwardly slightly and bring the friction-drive wheels 41, 4i' of the motors 36, 36 into snug engagement against the inner face of the rim 42. Furthermore, the motors are, in effect, balanced against each other so as to apply forces against the rim 42 at diametrally opposite points, thereby holding the wheel 43 in dynamic balance. Furthermore, the toggle switches 33, 38 are so arranged that one or both motors can be turned on or off, thus making it possible to drive the wheel 43 with either one or both motors. lt is, of course, obvious that with both motors energized, the wheel 43 will be driven with twice the power and speed.

In use, either one or both of the motors 36, 36', may be turned on, depending upon the speed and power requirements of the particular grinding operation about to be performed. Thereupon, a suitable abrasive compounds, such as jewelers rouge or any other similar material, may be applied to the upper horizontal surface 44 of the wheel 43 and the object to be ground manually applied to the abrasive-coated surface. The object to be ground is moved by the mechanic in any desired direction across the surface 44 with such speed as may be desired. As the object is moved inwardly toward the center of the wheel 43, it will be ground at relatively slow speed and contrariwise as it is moved toward the outer periphery of the wheel 43, it will be ground at a much more rapid rate, since the lineal speed of movement of the wheel 43 is greater at its outer edge than inwardly toward its center. Furthermore, as the workman moves the work from one side of the wheel diametrally across through the center and toward the opposite side of the wheel, the surface being ground will be subjected to a graded grinding operation in which it is rst ground at relatively high speed and then is ground at progressively reduced speed until it reaches the center of the wheel. At this point, the grinding speed is' practically zero. As the surface being ground passes through the center of the wheel 43 and moves toward the opposite side, it will be ground in the opposite direction at increasing speed as it moves toward the outer periphery of the wheel 43. If the workman desires to grind an object at a single selected grinding speed he may hold it in a stationary position against the wheel 43 and may, by positioning it at various radial distances from the center of the wheel 43, select a wide range of dilferent grinding speed. The grooves 45 prevent loose abrasives and other material from working into the surfaces of the parts being ground, honed, or lapped, and

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. A surface grinder comprising a base, a grinding wheel operatively mounted for rotative movement upon the base and in spaced relation thereto, said grinding TJI (itl

wheel having a peripheral skirt extending from the under side thereof in the direction lof the base, a pair of electric motors swingably mounted on opposite sides of the base and being provided with friction-wheels engaging the inner face of the skirt at diametrally opposite portions thereof, and spring means interposed between said motors and biasing them against each other and outwardly into frictional engagement with the skirt at diametrally opposite positions thereon.

2. A surface grinder comprising a base, a grinding wheel operatively mounted for rotative movement upon the base and in spaced relation thereto, said grinding wheel having a peripheral skirt extending from the under side thereof in the direction of the base, a pair of electric motors swingably mounted on opposite sides of the base and being provided with friction-wheels engaging the inner face of the skirt at diametraily opposite portions thereof, and spring means interposed between said motors and biasing them against each other and outwardly into frictional engagement with the skirt at diametrally opposite positions thereon, said motors each being controlled from separate switches so that either or both of said motors can be turned on or oif at will.

3. A surface grinder comprising a base, an upright spindle on the base, a grinding wheel operatively mounted for rotative movement upon the spindle in upwardly spaced relation to the base, said grinding wheel having a peripheral skirt extending from the under side thereof in the direction of the base, a pair of electric motors swingably mounted on opposite sides of the base and being provided with friction-wheels engaging the inner face of the skirt at diametrally opposite portions thereof, and a pair of spaced parallel compression springs located equidistantly on opposite sides of the spindle interposed between said motors for urging said motors and frictionwheels outwardly with respect to each other.

4. A surface grinder comprising an open-topped hollow vertical cylindrical housing having a horizontal bottom wail, e shaft disposed centrally of and extending coaxially upwardly from the bottom wall, a circular grind ing member having an upwardly presented flat grinding face and being provided centrally' of its under face with a downwardly extending tubular sleeve for bearingwisc disposition over and around the shaft, said sleeve being provided at its lower end with a diametrally enlarged annular iiange, said circular grinding member also being provided adjacent its outer periphery with a depending annular sltirt having an inwardly presented cylindrical face concentric with the shaft, a spring-biased pin mounted in and extending radially through the` cylindrical housing, said pin being slidably engaged at its inner end with said flange whereby to hold the grinding member on the shaft, and driving means mounted within the housing and having friction means for drivingly engaging said cylindrical face of the skirt.

5. A surface grinder comprising an open-topped hollow vertical cylindrical housing having a horizontal bot'- tom wall, a shaft disposed centrally of and extending coaxially upwardly from the bottom wall, a circular grinding member having an upwardly presented at grinding face and being provided centrally of its under face with a downwardly extending tubular sleeve for bearingwise disposition over and around the shaft, said sleeve being provided at its lower end with a diametrally enlarged annular flange, said circular grinding member being thus supported in upwardly spaced relation to and extending across the upper top of the housing, said circular grinding member also being provided adjacent its outer periphery with a depending annular skirt having an inwardly presented cylindrical face concentric with the shaft, a springbiased pin mounted in and extending radially through the cylindrical housing, said pin being slidably engaged at its inner end with said ange whereby to hold the grinding member on the shaft, and driving means mounted within the housing and having friction means for drivingly engaging said cylindrical face of the skirt.

6. A horizontal lapping machine comprising a substantially circular horizontal base, a pair of ilat plates rockably mounted at their lower margin upon the base and extending upwardly therefrom in approximately vertical position, said plates being located equidistance on opposite sides of and in parallelism with a diametral line across the base, an upstanding post disposed centrally of and projecting upwardly from the base, a horizontal lapping wheel having a centrally located tubular bearing sleeve projecting downwardly from its underface and fitted journalwise upon the post, said lapping wheel being 1 provided adjacent its outer peripheral edge with a depending annular skirt, a pair of substantially identical electric motors each being mounted respectively upon the outwardly presented faces of said plates, said motors having upwardly projecting shafts provided with drive pulleys respectively disposed in frictional engagement upon the inwardly presented face of the skirt at diametrically opposite locations thereof for frictionally driving said lapping wheel, a pair of spaced parallel stabilizing rods disposed in substantially equidistant relation on opposite sides of the post and each being slidably engaged at its opposite ends and extending longitudinally between said plates, and a washer lixed upon said rod approximately midway between said plates and compression springs encirclingly disposed around each of said rods on opposite sides of the washer for exerting outward pressure against said plates whereby to resiliently rock said plates and the motors supported thereby outwardly for causing the pulleys to engage the skirt with equalized frictional pressure.

References Cited in the frle of this patent UNITED STATES PATENTS 182,830 Johnson Oct. 3, 1876 1,057,344 Hayward Mar. 25, 1913 1,176,895 Hatfield Mar. 28, 1916 1,198,413 Brenner Sept. 19, 1916 1,293,622 Roberts Feb. 4, 1919 1,660,489 Hirvonen Feb. 28, 1928 1,742,217 Renwick Jan. 7, 1930 2,092,714 Flygare Sept. 7, 1937 2,097,071 Lichten Oct. 26, 1937 2,264,598 Stainbrook Dec. 2, 1941 2,296,751 Van der Woude Sept. 22, 1942 FOREIGN PATENTS 994,512 France Aug. 8, 1951 

